Geared motors are used as driving power source of a power window apparatus, a sunroof apparatus, etc. of vehicles. The geared motor has a motor portion in which a rotation shaft and an armature having a commutator are rotatably installed in a yoke housing, and a speed reduction portion in which a speed reduction mechanism for decelerating a rotation of the output shaft of the motor portion is installed in a gear housing. It is desirable to suppress an electromagnetic noise that is generated by a sliding contact of brushes on a commutator, when the motor is used in the power window apparatus, the sunroof apparatus, etc. for vehicles.
JP-2004-56896-A and its counterpart US-2004-0012296-A1, for example, disclose a motor that has a capacitor therein to suppress this electromagnetic noise. Each of a pair of power supply lines, that is, a pair of brushes of the motor, is provided with a capacitor. One terminals of the capacitors are connected to the power supply lines. The other terminals of the capacitors are connected to the yoke housing of the motor to establish groundings.
The yoke housing, however, is not necessarily grounded to a vehicle body, to connect the other terminal of the capacitor only to the yoke housing. That is, the member, to which the capacitor is grounded, is small, so that the capacitor cannot efficiently suppress the electromagnetic noise. Therefore, it is considered to improve the noise suppressing performance of the capacitor.